1. Field of the Invention
The present invention relates to laundry washing machines and more particularly to industrial washing machines.
2. Description of the Prior Art Industrial laundry washing machines having multiple washing compartments have been available for some time. Many of these machines comprise a horizontally mounted generally cylindrical chamber having a conveyor worm or auger screw rigidly mounted in the interior of the chamber so that several washing compartments are defined between the surfaces of the auger screw. Laundry to be washed in these machines is typically placed in the first compartment on one end of the machine and wash water containing proper detergents or other treating chemicals is introduced into the compartments. Introduction of wash water is typically achieved either by spraying it into the compartment from performations formed in the hub of the auger screw or by continuously supplying wash water from one end of the chamber and allowing it to flow through performations formed in the transfer screw walls and out the opposite end of the chamber.
With laundry and wash water in the compartment, the machine will generally be oscillated through a predetermined angular range several times which agitates the laundry in the wash water. At the end of this oscillation period, the machine will be rotated through a 360.degree. arc which transfers the laundry to the next compartment in the chamber where it is again oscillated with wash or rinse water. This process is repeated until the laundry reaches the last compartment where it is removed from the machine.
Washing machines of the type described above are known in the laundry industry as mono-shell or single drum machines, examples of which are illustrated and disclosed in U.S. Pat. Nos. of Stoll et al (4,210,004) and Schmidt et al (4,494,265).
Another prior art washing machine design known as a double drum machine comprises several individual cylindrical inner washing drums connected together in series with passageways along their longitudinal axes. These inner drums are rotatable within fixed outer drums which contain wash water or other chemicals. Laundry to be washed is transferred to each inner drum in turn where wash water or other treating chemicals within the fixed outer drum enter through holes in the inner drum. The drum is then oscillated or rotated within the fixed outer drum to affect washing. At the end of each wash cycle, the laundry is transferred through the passageway to the next inner drum for the next wash cycle. This process is repeated for each washing drum until the laundry is clean. This type of machine is disclosed in U.S. Pat. Nos. to Pellerin et al (4,485,509), Harrsch (4,156,358), Hugenbrunch (4,109,493) and Bhaysar (Re. 30,214).
The prior art washing machines exhibit several shortcomings in operation. In the continuous flow wash water machines, water intermixes between chambers so that batches of cloths of different colors cannot be washed in the machine at the same time. In addition, large volumes of water are required to maintain the flow of the wash water through the machine and complicated valve and pipe systems are required to introduce detergent and other treating liquids into the wash water flow.
Machines with nonperforated auger screw walls in which wash water and other treatments are introduced into each chamber through a pipe extending along the axis of the screw also require complicated drain systems to remove the water from each compartment at the end of each wash cycle so that it will not be transferred with the cloths to the next washing compartment. In these as well as other prior art designs, dirt and heavy soil material washed from the laundry is often transferred with the laundry to the next compartment because it is too large to drain through the drain system with the water.
Prior art machines comprising series of individual inner washing drums rotatable within fixed outer drums tend to be even more complicated than continuous flow machines. Because of the individual compartments, complicated means of delivering wash water to each drum and draining it therefrom at the end of a wash cycle is required. These machines use a large quantity of water and often have a plurality of valves and flow pipes to clog.